Maintenance Electrician Exam #2

In general, branch-circuit conductors serving continuous loads, such as luminaires in an office building or commercial plant, shall have an ampacity of NOT less than _____ percent of the load. a) 125 b) 115 c) 150 d) 80

A: 125 Ref: 210.19(A)(1)

In general, branch-circuit conductors that supply a single AC motor used in a continuous-duty application shall have an ampacity of NOT less than _____ percent of the motor's full-load running current rating. a) 125 b) 100 c) 150 d) 115

A: 125 Ref: 430.22(A)

A SPD (surge arrester or TVSS) device may be installed on circuits of up to _____ volts. a) 150 b) 300 c) 600 d) 1,000

C: 600 Ref: 285.3(1)

In general, electrical metallic tubing (EMT) shall be securely fastened within ____ of each junction box, panelboard, or other conduit termination. a) 3 feet b) 6 feet c) 8 feet d) 10 feet

A: 3 feet Ref: 358.30(A)

One horsepower is equal to _____ watts. a) 746 b) 1,000 c) 1,250 d) 1,500

A: 746 Ref: General Knowledge

Given: an electrical metallic tubing (EMT) 50 feet in length to be installed will contain a total of nine conductors. Six of these wires are considered to be current-carrying. What is the derating factor, in percent, that must be applied to the ampacity of the current-carrying conductors? a) 80 percent b) 70 percent c) 60 percent d) 50 percent

A: 80 percent Ref: Tbl. 310.15(B)(2)(a)

Compliance with the provisions of the NEC® will result in an electrical installation that is essentially _____. a) free from hazard b) a good electrical system c) an efficient system d) all of these

A: free from hazard Ref: 90.1(B)

When an insulated black conductor is identified by three continuous white stripes along its entire length, it is considered a/an _____. a) grounded conductor b) ungrounded conductor c) equipment grounding conductor d) phase of a delta-connected system

A: grounded conductor Ref: 200.7(A)(2)

What is the approximate MAXIMUM distance a single-phase, 240-volt, 42-ampere load may be located from a panelboard, given the following related information: (1)copper conductors, K = 12.9; (2)size 8 AWG THWN/THHN conductors are used; (3)limit voltage drop to 3 percent a) 50 feet b) 110 feet c) 160 feet d) 195 feet

B: 110 feet Ref: Chapter 9, Table 8; Distance Formula Sol: VD = 240 volts x 3 percent = 7.2 volts D = (CM x VD) / (2 x K x I) = (16,510 x 7.2) / (2 x 12.9 x 42) = 118,872 / 1,083.6 = 109.7 ft.

In general, the overcurrent protection for size 12 AWG copper conductors, regardless of the insulation type, shall not exceed _____ amperes. a) 15 b) 20 c) 25 d) 30

B: 20 Ref: 240.4(D)(5)

The NEC permits electrical trade size 3⁄8 inch flexible metal conduit (FMC) to be used for tap conductors (fixture whips) to luminaires, provided the length of the flex does not exceed _____. a) 4 feet b) 6 feet c) 8 feet d) 10 feet

B: 6 feet Ref: 348.20(A)(2)c

Unless listed and identified otherwise, terminations and conductors of circuits rated 100 amperes or larger shall be rated at _____. a) 60 degrees C b) 75 degrees C c) 90 degrees C d) 120 degrees C

B: 75 degrees C Ref: 110.14(C)(1)(b)(1)

When circuit breakers are used to switch 120-volt and 277-volt, high-intensity discharge lighting branch-circuits, the circuit breakers shall be listed and marked _____. I) SWD II) HID a) I only b) II only c) either I or II d) neither I nor II

B: II only Ref: 240.83(D)

Cord-and-plug-connected vending machines located in break rooms of commercial establishments are required to be provided with _____. I) a power supply cord not smaller than size 12 AWG with a length not exceeding 4 feet. II) GFCI protection a) I only b) II only c) both I and II d) neither I nor II

B: II only Ref: 422.51

The reason the NEC® requires all grounded and ungrounded conductors of a common circuit to be installed together in the same ferrous metal raceway is to reduce _____. a) expense b) inductive heat c) voltage drop d) resistance

B: inductive heat Ref: 300.20(A)

Under normal conditions, an equipment grounding conductor will _____. a) improve current flow b) not carry current c) carry current d) reduce circuit resistance

B: not carry current Ref: Art. 100; Trade Knowledge

When an electrical trade size 3⁄4 inch electrical metallic tubing (EMT) is in excess of 24 inches in length, the conduit is permitted to contain no more than _____ size 10 AWG conductors with THWN insulation. a) six b) ten c) eight d) fourteen

B: ten Ref: Annex C, Tbl. C.1

Given: a 9 kW rated 208-volt, three-phase electric steamer is to be installed in the kitchen of a commercial establishment, the steamer will draw _____ amperes. a) 43 b) 4.3 c) 25 d) 75

C: 25 Ref: 3-Phase Cureent Formula Sol: I = P/E x 1.732 I = (9 kw x 1,000) / (208 x 1.732) = 9,000 watts / 360.25 = 24.9 amperes

A motor with nine leads coming out of it is a _____. a) two-phase motor b) two-speed motor c) dual-voltage motor d) multi-speed motor

C: dual-voltage motor Ref: Trade Knowledge

For continuous-duty motors, the motor nameplate current rating is used to determine the size of the _____ required for the motor. a) disconnecting means b) branch-circuit conductors c) motor overload protection d) short-circuit protection

C: motor overload protection Ref: 430.6(A)(2)

The MINIMUM required width of the working space in front of panelboards, switchboards, disconnects, and motor controllers shall be the width of the equipment or _____ , whichever is greater. a) 2 feet b) 3 feet c) 4 feet d) 30 inches

D: 30 inches Ref: 110.26(A)(2)

A branch-circuit inverse-time circuit breaker rated in amperes shall be permitted as a controller for _____. a) continuous-duty motors b) intermittent-duty motors c) torque motors d) all motors

D: all motors Ref: 430.83(A)(2)

In computing the load of luminaires that employ ballast, transformers, or autotransformers, such as fluorescent lighting units, the load must be based on the _____. a) total wattage of the lamps b) VA of the lamps c) length of the lighting fixture d) ampere ratings of the complete units

D: ampere ratings of the complete units Ref: 220.18(B)

On a four-wire, delta-connected system, the conductor having the higher voltage to ground (high-leg) shall be identified as _____ in color, if the grounded conductor is also present to supply lighting or similar loads. a) white b) red c) green d) orange

D: orange Ref: 110.15

An insulated branch circuit conductor with a continuous yellowcolored insulation is considered to be a/an _____. a) equipment grounding conductor b) grounded conductor c) switch-leg d) ungrounded conductor

D: ungrounded conductor Ref: 310.12(C); 200.6; 250.119